DL240 REPAIR

1924 Volvo 240

I am looking to buy a 89 volvo dl240 wagon for my son, who will be 16. The sellers bought this car new and seem to have maintained it well. It has 140k miles and appears to be in good shape. We are told by the sellers it requires engine mounts replaced because the engine vibrates upon starting. What else do we need to look for in a car of this vintage and in general how much should we expect to spend in repairs for a car of this age? Thanks for your assistance.